Until the song reached Earth, all had gone well. Young people selected for their emotional stability seemed able to withstand the terrible loneliness. But now--the song. And the whisperings that were threatening to disrupt the whole recruiting campaign. These young people were subject to the influences of their parents, churches and sweethearts. Even this tenuous wisp of smoke might indicate fire. And if the verses of the song became one shade more ribald, G.F. would whistle for qualified applicants. A wide open scandal could wreck the whole enlistment program. Back on earth the problem had presented Duncan with a provocative challenge. Now, 20 days out, with 42 days travel ahead, his thoughts were wrapping into a tight spiral of resentment. His imagination had run the gamut of every possible situation he might find, each more lurid and revolting than the last. He cursed man's lustful nature that made this whole mission necessary, and in particular he blamed the Mars colony for the physical discomfort he was being forced to endure. What kind of medal might they award him for spying on a herd of billy-goats and weak-willed nannies? A buzzer vibrated under his arm. It was his turn for exercise. Wearily he unfastened the webbing that strapped him to the g-couch and hauled his way forward to the tiny physical therapy chamber. They were in so-called free flight, but the lurches required that he hold fast to the padded rail and move hand-over-hand. There would be the tension exercises, then a "shower" with a damp towel. Then meal time. He made a face at the thought. So far he had been able to eat fewer than a dozen meals orally. His arms already were becoming freckled with scars from the intravenous feedings and anti-vertigo injections. * * * * * To his considerable surprise he was able to step through the air-lock and descend the steep, cleated ramp to the surface of Mars under his own power. The setting sun was a tiny, hot eye burning across the reddish orange plains. A light breeze refreshed his face after the rank humidity of the space ship. But the mask through which he breathed and the oxygen bottle on his back reminded him it was an unfriendly wind, the movement of a thin ocean of nitrogen in which a man could drown within minutes. He sucked gratefully at the low-pressure oxygen, and in silence shuffled after their guide. Gravity was only a third of earth's. After weeks of free-fall and the last hours of heavy deceleration, the replacements stumbled drunkenly seeking their land legs. A half mile from the ship the lights of the mine and lesser glow from the settlement alongside guided their course. As they neared the village he could make out a sprawl of squat, box-like buildings of a dull, silvery finish. They were the thin-walled, magnesium alloy structures in which Duncan would sleep, eat and spy until the next ship-landing.